A composition for injection consisting of peptides in the form of powder, and a diluent consisting of sodium hydrogen carbonate is disclosed in WO 2007/028573 for the vaccination of renal cell carcinoma. However, this formulation has various disadvantages. The main disadvantage is the poor solubility rendering its application very difficult during any application such as in clinical use.
To dissolve the powder in the composition, the vial containing the peptides to be dissolved and the diluent have to be shaken vigorously for three minutes, then submitted to ultrasound homogenation for one minute, and again to be shaken for one minute. This treatment cannot be applied by all physicians in their practices, as they often lack the equipment as required, and the archived mixture thus might not be homogeneous as required for an effective use.
An additional problem with the composition relates to the fact that, given the speed of dissolution of the active ingredients using sodium hydrogen carbonate in the given concentrations, the resulting solution can only be used for about 30 minutes.
Further, the characteristics of the above formulation change over time, which renders a safe use nearly impossible. After storage of the disclosed formulation for 12 months using different temperatures ranging from −20° C. to +25° C., no clear solution could be produced, even after using an ultrasound homogenator for several minutes.
Thus, there remains a need for novel peptide formulations with enhanced solubility and enhanced moistening of the lyophilisate, in order to provide a safe an effective preparation, in particular in case of an anti-cancer vaccine. The present invention fulfills this need.